Dual generator ventilation



1943- c. A. ATWELL Erm.

nun. esumm'on 'vmmmno Filed April 30, 19:1.

INVENTORS C/areace A. Afwe/l and I Ev'ch a Mueller:

BY 9 a I C ATTORNEY tgglTNE-fS/ES:

Patented Nov. 16, 1948 I DUAL GENERATOR VENTILATION Clarence A. Atwell, Pittsburgh, and Erich 0. Mueller, Irwin, Pa., assignors to Westinghouse Electric Corporation, East Pittsburgh, Pa., a I corporation of Pennsylvania Application April 30, 1947, Serial No. 745,024

4 Claims.

Our invention relates to the ventilation of direct-current dynamo-electric machines, and it has particular relation to the ventilation of a pair of coaxial or aligned direct-current generators or motors. While our invention is not altogether limited thereto, it was primarily designed for the ventilation of dual-generators in large turbineelectrie railway-locomotives, where space-restrictions are stringent, and where ordinary ventilating-methods are inadequate in one way or another.

An object of our invention is to provide means for thoroughly ventilating both the armature and the commutator of a commutator-type dynamoelectric machine by means of a longitudinally moving blast of ventilating-air which passes first over the armature then over the commutator, and thence axially out of the machine, in combination with a special means for cooling the commutator and the brushes bearing thereon, in spite of the fact that the commutator-diameter is smaller than the armature-diameter.

A further object of our invention is to provide a dual-generator ventilating-system utilizing a single source of forced ventilating-air, with means for obtaining thorough ventilation of all parts of both machines.

With the foregoing and other objects in view, our invention consists in the systems, combinations, parts and design-methods hereinafter described and claimed, and illustrated in the accompanying drawing, the single figure of which is a somewhat diagrammatic longitudinal sectional view through a dual-generator illustrative of our invention.

In the illustrated embodiment of our invention, we show a dual-generator assembly, comprising a pair of coaxial or aligned direct-current generators or other dynamo-electric machines, I and 2, which have a continuous tubular outer framemember 3 for the two machines, said tubular outer frame-member being in two parts, 3i and 32, which are joined together in alignment with each other, as shown at 4, preferably at some point between the two machines. Each machine has a plurality of salient pole-members 5, which project inwardly from the outer frame-member 3 to provide the fie1d-member of that machine. There is a common shaft 6 for the two machines, and each machine has a separate armature-meml0, which bear on each of the commutators 8 of the two machines, respectively. In practically all cases, it is desirable, for various reasons, that the commutators 8 should have a smaller outer diameter than their armature-members I, and this circumstance imposes one of the limitations which are overcome in our present invention.

The particular dual-generator which we have shown in our drawing is a part of a dual-generator assembly which, in combination with its mounting, constitutes the subject-matter of our copending application, Serial No. 745,080, filed concurrently herewith. In that particular combination, one end of the shaft 6, such as the end which passes through the right-hand generator 2, is rotatably supported in a bearing I I which is carried by a front end-member I2 which is carried by, or either integrally or detachably united to, that end of the outer frame-member 3. The other end of the shaft 6 is provided with a drive-flange or coupling-flange l3, by means of which it is adapted to be connected on, as an extension of another shaft (not shown) which is suitably journalled, beyond that end of the dual-generator aggregate which we are claiming in our present invention. Thus, the shaft-end of the shaft 6, which passes through the left-hand generator I, is provided with the aforesaid coupling-flange I3; and the outer frame 3, at that end of the assembly, is provided with a front end-member H which is either integrally or detachably united to the outer frame 3 at that end of the assembly. This end-member, however, does not support a hearing, but is provided with a bore I5 which is just a trifle larger than the outer diameter of the coupling-flange I3, so that there is clearance in the normal running of the machines.

Both of the end-members I 2 and M are provided with one or more openings I6 for providing an exhaust-vent or vents for a substantially axially or longitudinally moving stream of exher I which is carried by the shaft in cooperative relation to the field-poles 5 of that machine.

Each machine also has a commutator-member 8 which is carried by the shaft at the outer end of the armature-member I of that machine, the

haust-air from-each end of the assembly.

In addition, each machine has one or' more outer-end (or front-end) air-inlet perforations I I, such as are shown at the bottom of the outer frame-member 3, at points which are substantially radially opposite to the inner ends of the respective commutator-members 8. Preferably also, a baflle-means I8 is provided, adjacent to the outer-end air-inlet perforations at the respective ends, of the dual-generator aggregate, these bailie -means i 8 extending inwardly from the outer frame 3, toward, but not altogether to, the inner end of the commutator 8 at that end of the machine, between the aforesaid outer-end airinlet perforations i I and the field-pole members of the machine at that end of the assembly.

The outer frame-member 3 is also provided with one or more centrally located air-inlet openings l9, between the two machines i and 2, so as to admit a stream of forced ventilating air into the intermediate ventilating space 9 at the back ends of the two machines.

In the. particular form of embodiment of our invention which is shown in the drawing, it was desirable to utilize a common supply of ventilating-air for both machines, and it was found best to have the air enter the dual-generator from.

the bottom, as indicated symbolically by the duct 4 20, and the arrows therein, which are intended as a diagrammatic indication or representation of means for providing a supply of forced ventilating-air for both of the machines. Most of this air enters the dual-generator assembly through the inlet-openings or openings it! at the rear (or centrally disposed) ends of the machines. Thence the air passes axially out'of the assembly, flowing in botn directions toward the exhaustopenings it in the respective end-members i2 and H, In its axial passage through the machine, this main body of the ventilating-air flows first past the salient pole-members 5 of the machine at that end of the assembly, flowing in the annular space between the tubular outer frameportion 3 and the outer diameter of the armature i of the machine at that end of the assembly. Then the axially flowing air, as it leaves the region of the salient pole-members 5 and the armature i, passes over the commutator ii and the brushes iii, as indicated by the arrows 22, before the ventilating-air is discharged axially through the exit-openings it at that end of the assembly. 4

However, due to the fact that the commutatordiameters are somewhat smaller than the diam eters of the peripheral surfaces of the armaturecores, it is somewhat difficult to deflect this moving air down toward the cylindrical peripheral surface of the commutator 8. For this reason, we provide means for bleeding off a relatively small volume of air from the common supplysource 20 of ventilating-air, outside of the tubular outer frame-portion 3, that is, underneath this frame, inthe illustrated embodiment of our invention; and we direct this small quantity of bled-off air into each machine, so that it flows in a radial direction toward the rear end of the commutator-member 8 of that machine, entering through the previously described outer-end air-inlet perforations ii.

It will be noted, in the particular embodiment of our invention which is illustrated, that the supply-source of ventilating-air comes to the assembly from the left, underneath the machine which has been numbered i, and passes on to the center of the assembly, where the air passes upwardly through the centrally-disposed intakeopening or openings ii). To bleed off a, small quantity of this air-supply for the commutatorend of the left-hand machine i, it is only necessary to let the bottom of the machine be the top of the air-duct 2t, so that the outer-end inletopening or openings ill, at the left-hand end of the assembly will divert a small portion of the air, as shown by the arrows 23, To bleed oil. a

inlet perforation or perforations i! at the righthand end of the aggregate, so as to provide a small air-supply for the commutator 8 of the 'righthand generator 2, as indicated by the arrow 25.

It will be understood, of course, that it is possible to provide as many central and outer-end air-inlet perforations i9 and H, as may be desired, at points spaced as far around the circumference as may be necessary in any particular case. It is further to be noted that the bailles i8 perform a useful function in assisting in diverting the longitudinally or axially flowing air inwardly toward the commutator 8, after passing axially around the salient pole-members 5, as indicated by the arrows 26.

Also, while we have so far described more particularly a simple ventilating-scheme in which only the outer peripheries of the armatures l are ventilated, it is possible, and usually desirable, as shown, to provide various armatureventilating ducts in and beneath the armature, as indicated at 2i and 28, some of this armature ventilating-air passing out underneath the commutator-members 8, as indicated-by the arrows 29, and some of it passing out radially past the armature terminal-conductors M, which lead to the commutator-necks e2, as indicated by the arrows 33. These and similar details of armature-cooling are known in the art, and we lay no claim thereto, except in combination with the other special features which we have provided, as herein described and claimed.

It is obvious, therefore, that our invention is not limited to the particular details of the form of embodiment which we have chosen for illustration, and we desire that our appended claims shall be accorded the broadest construction consistent with their language.

We claim as our invention:

1. A dynamo-electric machine comprising: a stationary field-member having a tubular outer frame-portion which provides a magnetizable yoke-member, a plurality of salient pole-members projecting inwardly from the yoke-member, a rotatable shaft, an armature-member carried by the shaft in cooperative relation to the field-poles, a commutator-member carried by the shaft at the front side of the armature-member, said fieldmember carrying brushes bearing on said commutator-member, said commutator-member having a smaller outer diameter than said armaturemember, said tubular outer frame-portion having one or more front-end air-inlet pcrforations radially opposite the inner end of said commutator-member, said frame having a front endmember having one or more openings for providing an exhaust-vent or vents for a substantially axially moving stream of exhaust-air from the machine, means for providing a supply of ventilating-air at the rear end of the machine, whereby a stream of cooling-air flows axially through the machine, past the salient pole-members in the annular space between the tubular outer frame-portion and the outer diameter of the armature-member, then over the commutatormember and out through said exhaust-vent or vents, and means for bleeding off a relatively small volume of air from said rear-end supply of ventilating-air, outside of the tubular outer frame-portion, and directing it radially into the two machines, each machine having an armature- I member carried by the shaft in cooperative relation to the field-poles of that machine, each machine having a commutator-member carried by the shaft at the outer end of the armaturemember of that machine, said tubular framemember carrying brushes bearing on each of said" commutator-members, said commutator-members having smaller outer diameters than their armature-members, said tubular frame-member having one or more outer-end air-inlet perfora tions radially opposite the inner end of each of said commutator-members, said tubular framemember having two end-members each having one or more openings for providing an exhaust vent or vents for a substantially axially moving stream of exhaust-air from the machine at that end of the assembly, said tubular frame-member having one or more centrally located air-inlet openings between the two machines, means for providing a common supply of ventilating-air for both machines, entering said tubular framemember through said centrally located air-inlet openings, and thence flowing past the salient pole-members in the annular space between the tubular outer frame-portion and the outer diameter of the armature-member of each machine, then over the commutator-member and out through said exhaust-vent or vents, and means for bleeding of! a relatively small volume of air from said common supply of ventilating-air, outside of the tubular outer frame-portion, and directing it radially into each machine toward the commutator-member, through said outerend air-inlet perforation or perforations.

3. The invention as defined in claim 1, characterized by said machine having a baffle-means extending inwardly from the tubular-outer frameportion toward, but spaced from, the inner end of the commutator-member, between said 'frontend air-inlet perforation or 'perforations and the salient pole-members.

.4. The invention as defined in claim 2, characterized by said combination including baffle-means extending inwardly from the outer frame-member toward, but not altogether to, the inner end of the commutator-member of each machine, between the outer-end air-inlet perforation or perforations and the salient pole-members of the respective machines.

CLARENCE A. ATWELL. ERICH o. MUELLER.

naraaancas orran The following references are of record in the file of this patent:

UNITED STATES PATENTS Germany Apr. 25. 1934 

